Silicone rubber sponges possess superior thermal resistance, superior weather resistance, light weight, and a low thermal conductivity. For these reasons, the silicone rubber sponges are used in various sealing elements such as packing, gaskets, o rings, and the like; rollers and belts of image-forming apparatuses such as copying machines, printers and the like; automotive parts such as hood buffering pads, engine vibration insulators and the like; and other applications.
Compositions for obtaining silicone rubber sponges are known. For example, Japanese Unexamined Patent Application, First Publication No. 2005-62534 describes a sponge-forming silicone rubber composition of an addition-reaction curing type which contains water and a surfactant, and a silicone rubber sponge obtained from the aforementioned composition is used as a constructional material of a fixing roller of an image-forming apparatus.